Why does Table.getItem(Point) always return the item from column zero?

Question

I've implemented a class to give me a more flexible tooptip for the org.eclipse.swt.widgets.Table class. As I'm sure you all know, by default you get one tooltip for the whole table - and not individual tips for each cell.

My object creates a number of listeners to implement it's own location sensitive tooltip, however, when I call Table.getItem(Point) to get the TableItem (or cell) over which the mouse is hovering it always returns the cell from column 0 of the correct row.

The table in question is created by a TableViewer with this incantation ...

viewer = new TableViewer( parent, SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL | SWT.FULL_SELECTION );

Wherever am I going wrong?

Answer 1

The answer, in the end is that TableItem represents a row, and not a cell within a row. This little method will fetch the column number for you ...

/**
 * Get the column from the given TableItem and Point objects 
 * @param pt
 * @param item
 * @return -1 if no column is found
 */
public static int getColumn( Point pt, TableItem item )
{
    int columns = item.getParent().getColumnCount();
    for (int i=0; i<columns; i++)
    {
     Rectangle rect = item.getBounds (i);
     if ( pt.x >= rect.x && pt.x < rect.x + rect.width ) return i;
    }
    return -1;
}

NB: Rectangle.intersects( Point ) can fail if you hover exactly over the table edges, so I've used a simple X comparison instead.